CheckingIf you click 'Check' the system will check for incorrect squares. If 'Show mistakes when checking' is checked they will be marked in red.

UniquenessEach puzzle has exactly one solution, which can be found using logic alone and no guesses are ever required. If you think you've found another solution, then please double check the rules. If you still think you've found another solution, then please email us and we'll try to help.